Recording pitchometer



July 15, '1941.

I. D. EBY

RECORDING PITCHOMETER Filed Sept. 9, 1939 5 Sheets-Sheet l ATTORNEY July 15,1941. 1. D. EBY 2,248,973.

RECORDING PITCHOMETER Filed Sept. 9, 1939 s Sheets-Sheet '2.

I I il 5 mnuuu lllluu mua III /VAN D. EBY

ATTORNEY July 15, 1941. D. EBY 2,248,973

RECORDING PITCHOMETERV Filed' Sept. 9, 1939 5 She ets-Sheet 3 VAN D. BY BY ATTORNEY July 15, 19 41. EBY 2,248,973

RECORDING PITCHOMETER Filed Sept. 9, 1939 5 Sheets-Sheet 4 INVENTOR lww 0. Ear

- ATTORNEY I. D.' EBY RECORDING-PITCHOMETER July 15, 1941.

5 Sheets-Sheet 5 Filed Sept. 9, 1939 INVENTOR /VAN D. EBY BY 2M? ATTORNEY Patented July 15, 1941 UNITED STATES PATENT OFFICE RECORDING PITCHOMETER Ivan D. Eby, Staten Island, N. Y. Application September 9, 1939, Serial No. 294,080

15 Claims.

The present invention relates to recording pitchometers, and is more particularly'directed toward improvements in recording pitchometers of the type shown and described in my co-pending application Serial No. 849,518, filed October 23, 1934 (to be issued as Patentfio. 2,172,368 on September 12, 1939).

The presentinvention contemplates recording pitchometers adapted to be constructed of heavy, extremely rigid parts capable of ready assembly and disassembly so that the devices maylbe disassembled for shipment and reassembled for use in difierent shipyards or plants. 7

The present invention contemplates arecording pitchometer wherein the cylinders on which the chart is made are supported on a radially shiftable carriage and mounted on horizontal axes, thereby reducing the overall vertical dimensions of the device and making it possible to construct a more rigid piece of apparatus.

The present invention also contemplates an arrangement whereby the normal vertical movement of the follower cooperative with the blade surface of the propeller is transmitted through cords to a horizontally movable marker or pencil adapted to cooperate with the wrapping on the horizontal cylinder.

A further object of the present invention is toprovide recording pitchometers having means to compensate for the increased periphery of the wrappings on the cylinder whereby the linear speed of the pencil point is identical with the linear speed of the carriage along the arm.

A further object of the invention is to provide a recording pitchometer having means whereby the same recording mechanism may be employed to obtain either the profile of the propeller blade surface in radial planes or can be employed to obtain the profiles of the propeller surface at specified radii.

Other and further objects will appear as the description proceeds.

While the invention is more especially designed for use in connection with cast metal propellers for water craft, it may be used on the patterns for such propellers on the blades of water pumps and water wheels, or on wood or metal air screws.

The accompanying drawings show, for purposes of illustrating the present invention, an embodiment in which the invention may take form, it being understood that the drawings are illustrative of the invention rather than limiting the same.

In the drawings:

Figure 1 is a perspective view of a recording pitchometer showing it mounted over the blade of a propeller;

Figure 2 is a top plan view of the recording pitchometer;

' Figure 3 is a side elevational view of the same;

- Figure 4 is a sectionalview on the'line 4-4 of Figure 2;' 4

Figure 5' is a vertical sectional viewtaken on the line 5-5 of Figure'3 with parts inelevation and parts broken away; v

Figure 6 is a fragmentary horizontalsectional view taken on the line 6-45 of Figures 5 and v7;

Figure 7 is an enlarged fragmentary elevational view taken in the same direction as Figure 3, parts being broken away and parts in section;

Figure 8 is a section taken on the line 80of Figure 7';

Figure 9 is a top plan view of the chart making mechanism, parts being in section;

Figure 10 is a front elevational view of the same; Figure 11 is a fragmentary sectional view taken on the line I I-Il of Figure '7 when certain parts of the mechanism are in a different position than shown in Figure '7;

Figure 12 is a diagrammatic illustration ofa chart showing profilesof the propeller blade surface at radial planes;

Figure 13 is a diagrammatic top'plan view'illustrating the use of the recording pitchometer for making charts of' the surface of the pro-.- peller blade at selected radii; and V Figure 14 illustrates a chart 'showingthe profiles of the propeller blade taken at a plurality of radii.

A conventional propeller hub is indicated; at P and the blades at B. The propeller is normally placed flat, as indicated in Figure 1,- and the pitchometer is secured to the upper face of the propeller hub. The pitchometer is supported by four legs I00 bolted to the propeller by bolts in-, dicated at I0l. The upper ends of these legs are secured by bolts IOI to a disk or plate I02..,.This plate is welded to an upwardly extending hub I03, see Figure 4. This hub is drilled to receive a centering device I03 and rotatably receives'a sector-shaped protractor I04 and a rotatable bracket I05. The bracket can be turned about the axis of the hub I03 and clamped in any selected position by means of a clamping device indicated at I00. The armsupporting bracket I05 is a heavy, rigid casting and provided with a flange I01 near the end, the end'beinginthe form 'of a round extension indicated at I08.'

A long tubular arm I09 has a flanged end, indicated at H0, and is secured to the flange of the bracket by bolts indicated at III. This arm is reinforced by four longitudinally extending guides H2 welded to the tube and ground accurately to shape and size. The outer end of the arm I09 carries a yoke H3 to which are secure'd tie members H4, the other ends of these tie members being secured to an inner yoke I I5, secured to the bracket I05, thereby forming a rigid structure with minimum deflection.

A carriage H6 is reciprocable along the arm I09. The carriage is here shown as being made out of a piece of tubing H1 which is provided with an inner carriage bracket H8 and an outer carriage bracket H9 of substantially larger diameter than the arm I09. The brackets H8 and H9 are the same, but of opposite hand, and are provided with pairs of rollers I20 mounted on studs I20 secured in eccentric bushings I2I locked in adjusted position by set-screws I2I, as indicated in Figure '7. These rollers bear on opposite faces of the guides or fins II2 carried by the arm I09, and when the rollers eccentrics are adjusted the carriage axis can be brought to exactly the proper position to coincide with the axis of the arm and so that the carriage will be oriented at the proper angle relative to the arm. In this way all parts carried by the carriage may be accurately leveled and plumbed so that they are in accurate relation with the center line of the prop'ellerI The carriage may be locked in any selected'position by a jamb nut H6.

The brackets H8 and H9 have vertically extending grooves I22 adapted to receive the tongue I23 on one face of a generally angle-shaped bar I23, as shown more clearly in Figures 6, 9 and 10. This bar is clamped to the bracket H8 (or to the bracket H9) by clamping members I24 and bolts I25. The other side of the angle member I23 has a tongue I23" as indicated, to slidably receive the grooves in the long legs of L- shaped brackets I26 and I21. The brackets I26 and I21 are clamped to the bar I23 by clamps indicatedat I28. They may be adjusted to the proper height according to the propeller being charted. The short legs I26 and I21 of bracket members I26 and I21 slidably support a vertical rod I29 carrying on its lower end a roller I30 adapted to cooperate with the upper surface of the propeller blade B. The rod I29 may be graduated in inches and a cooperable slidab-le pointer I29 carried by the angle member I23 may be employed in making measurements of rod movement.

Each of the brackets II and H9 has grooves I22 so that the rod I29 can be mounted either on the outer end of the carriage,;as indicated in Figures 1-10, or can be mounted on the inner bracket, as indicated in Figure 11. The dimensions of the parts are such that the movement of the rod I29 from one position to the other changes the radius at which the roller contacts the blade by one foot. This makes it possible to bring the follower nearer the blade axis for propellers of smaller diameter. The lower .guide I I2 carries graduations as indicated in Figures 3 and 7 to cooperatewith a pointer II6' The carriage brackets H8 and H9 carry longitudinally extending angles I3I and I32 which extend beyond the carriage brackets. These angle members support end brackets I33 and I34'extending upwardly above the radially extending arm I09 and rearwardly as indicated in the drawings. A longitudinally extending T-shaped bar I35 is secured to the brackets I33 and I34, and this bar is provided with a longitudinally reciprocable carrier I36 for a pencil I31 and pencil carrier. The angles, brackets and bar pencil carrier has suitable mechanism for releasably gripping a pencil and for pressing it against the paper wrapping W on the cylinder on which the record is to be made.

The pencil carrier has a clamping device I38 whereby it may be secured to a cord I39. This cord passes around pulleys I40 and I 4| secured to brackets I40 carried by guide bar I35 and is connected to the top and bottom of the rod I29, as indicated at I42 and I43, Figure 5. When the rod I20 is mounted on the right-hand or outer end of the carriage, the cord I39 passes around guide wheels, indicated at I44 and I45, so as to go to the ends of therod I29. When the assembly is as indicated in Figure 11, the cord is passed around similar guide wheels I44 and I45. The guide wheels are carried on brackets indicated at I46 and I41.

From the foregoing it will be apparent that for any setting of the radial arm I09 over the propeller blade there is a. corresponding position of the pencil I31 along the guide I35 for each elevation of the roller I30 as determined by the surface of the propeller blade. It is therefore apparent that by moving the carriage along the arm the follower I30 will be moved up and down according to the profile of the propeller blade in the radial plane under consideration, and the movement of thepencil I31 will correspond with the change in profile.

The brackets I33 and I34 rotatably carry a cylinder I50 on suitable bearings I 50 and I50 as indicated. To the rear of the cylinder I50 the brackets I33 and I34 carry a paper storage cylinder I5I. This cylinder is adapted to receive a substantial quantity of paper and is connected to a suitable spring device, such as a phonograph motor indicated at I 52, for maintaining tension on the paper. It is provided with a stop device I53 to prevent unwinding when the paper wrapping W is not secured to the cylinder I50. This wrapping can be secured to the cylinder, as indicated at the right hand of Figure 9, by suitable stickers.

The inner end of the cylinder I50 is provided withja drum I54 adapted to receive a cord I55. This cord is passed about a guide pulley I56 and when used to chart profiles in radial planes is secured to an anchorage I51 adjacent the propeller axis, so that when the arm I09 is turned relative to the axis, there will be no motion given the cord so long as the carriage is stationary. When the carriage is moved along the arm from the foot of the propeller toward the top, the cord will be pulled off of the drum and this will cause the drum and cylinder to rotate, drawing paper onto the cylinder I50 from the storage cylinder I 5|. Onreturn movement of the carriage toward the root of the propeller the paper will be automatically rewound onto the storage cylinder I5I.

Inasmuch as the periphery of the cylinder is small as compared with the length of the propeller blade being charted, it is necessary to wrap several layers of paper around the drum. The added layers of paper change the amount of paper wound on for each turn of the drum, and in order to compensate for this and insure that the linear speed of the paper at the pencil point is always identical with the linear speed of the carriage along the arm, the drum I54 is provided with spiral grooves to receive the cord, and these grooves are accurately cut on a cone of the proper taper to correspond with the thickness of the paper.

Plate or disk I02 carries a ring I60 which is marked at each 90 for four-bladed propellers and at each 120 for three-bladed propellers. This ring fits very tightly in the place in the groove which receives it, but can be adjusted when desired. The protractor I 04 is provided with a bearing plate I6I adapted to bear on the periphery of the disk I02 and this plate carries a clamp member I62 adapted to be clamped against the ring by a nut I63. As shown in Figure 4, the protractor and bearing plate have a sight opening I65 at the same radius as the ring I60. The bracket I05 has an extension I66 which carries a pointer I61, this pointer being adapted to be moved past the graduations at the edge of the protractor I04.

After the machine has been set up on'a propeller, so that it is accurately centered over the propeller axis and the carriage has been adjusted to proper position, the arm I 09 :is then brought to the center line of one of the propeller blades and clamped in this position. The zero on theprotractor is then brought opposite'the zero on the pointer, the protractor clamped into position and the ring I60 moved to bring one of its graduations opposite the center of the sight 0 opening I65, a sighting wirejnotshown, being usually employed to assist in making the adjustment. The arm clamp I06 is then released and the arm with pointer swung over the other blades and their center lines checked with the graduations on the ring I60. This will show how far the blades are displaced from the'proper position and, if the displacement is not too much, the best compromise set up for the center lines of the blades. The ring and protractor are then re-set. The pitchometer is in readiness for making the charts for the profiles of the blades in radial planes. Such a chartis indicated diagrammati cally in Figure 12. Here, the long, straight parallel lines indicate the desired profiles of the propeller blade in regularly spaced radial planes, and the dotted line indicates the line which would be drawn on the chart where the profile of the 'pro-' peller blade departed substantially fromthe desired profile. The lines will have different slopes according to the propeller design and may converge or diverge, depending upon whether or'not the propeller. has other than uniform pitch.

Where it is desired to obtain the profiles of the blade at the desired radii, the recording pitchometer is slightly rearranged and, instead of moving the carriage lengthwise of the arm,-the-car-' riage is clamped to the arm at each radius and the arm swung about the propelleraxis so that the roller I30, is turned from the-position shown in Figure 1 so that it will traverse the surface of the propeller along the arc. This-will move the recording pencil back and forth along the guide. In order to move the paper under the pencil, cord I55 is disconnected from the anchorage I51 and, by means of an extension, is wrapped about a pulley I10 as is more clearlyshown in Figure 13. This pulley is carried on a vertical'shaft 'I II, mounted in the arm I66, and provided at the lower end with a pinion I 12 which-is in mesh with a rack I13, secured to the protractor I04. With this arrangement the moving of the arm I09 about the propeller axis will shift the pinion I12 along the gear I13 and cause the pinion to rotate at an angular speed, depending upon the diameters of the rack and pinion. By selecting a pulley I10 of the proper diameter, it is possible to wind on an amount of cord which corresponds exactly with the length of the arc through which the rod I29 travels at the radius at which the carriage has been clamped. A series of pulleys I10 is provided so that by merely changing them one can obtain profiles of the propeller at selected radii from root to tip. This makes it possible to secure full size, accurate patterns of the propeller blade surface at selected points.

Figure 14 diagrammatically shows the type of chart to be obtained with the set-up shown in Figure 13. The heavy diagonal lines I1I, I12 and I13 illustrate the contours of a blade'surface at various radii, the steeper line I1I being nearer the root of the blade than the flatter lines to the right. For the working surface of the blade these lines will be straight or slightly curved according to the contour set up by the designer of the blade. The lines for the back face of the blade will be curved somewhat as indicated by the heavy dash line I15. The lines will be positioned along the chart according to the location given the pencil on the guide and the amount of paperwhich has been wrapped onto the cylinder before the particular line is drawn. The, spacings of'the'lines lengthwise of the chart have no function other than to facilitate segregating the chart lines. If along any selected line marks are placed indicated at X and X at a known angular spacing, then the overall pitch between these two points may be accurately checked.

From the foregoing, it will be seen that one can readily make on the same machine charts of both types for the surfaces of the propeller blade. After each chart is made it is removed from the machine, placed on the drawing table, and gone over carefully so as to ascertain how true the surface is. While on the drawing board suitable marks can be placed on the chartto show where material must be ground off to provide the desired surface and, in the case of the cross sectional charts, these can be compared with the drawings specified by the designer.

After a chart has been gone over on the drawing board and lines drawn representing the true surface desired, the chart is replaced on the machine and is then used as a guide for grinding operations.

It is obvious that the invention may be embodied in many forms and constructionswithin the scope of the claims, and I wish it to be 'understood that the particular form shown is but oneof the many forms. Various modifications and changes being possible, I do not otherwise limit myself in any Way with respect thereto.

v What is claimed is:

1. A pitchometer for preparing a chart to show the departures of the surface of a screw propeller blade or the like from an ideal blade surface whereby the pitch of the propeller may be recorded, comprising a radially extending swingable arm, means for rotatably supporting the arm coaxially of the propeller whereby the arm is adapted to be placed in various radial positions opposite the sloping surface of the propeller blade, a radially movable carriage on the arm, a carriage carried follower movable transversely thereof and held in contact with the blade surface being recorded Whereby'the position of the follower at any radius is a function of the radial position of the arm, a horizontal cylinder carried by the carriage, a self winding paper storage cylinder, a paper wrapping extending from the storage cylinder and-secured to the first cylinder, a follower actuated. recording marker. movable with the carriage and bearing on the paper wrapping, and means to turn the cylinders on their axes in response to movement of the carriage along the radial arm so as to move the paper wrappings under the marker.- r

2. A pitchometer such as claimed in claim 1, wherein the cylinder turning means includes a cord anchored adjacent the propeller axis and wound about a cylinder actuating drum.

3. A pitchometer for preparing a chart to show the departures of the surface of a screw propeller blade or the like from an ideal blade surface whereby the pitch of the propeller-may be recorded, comprising a radially extending swingable arm, means for rotatably supporting the arm co-axially of. the propeller whereby the arm is adapted to be placed in various radial positions opposite the sloping surface of the propeller blade, a radially movable carriage on the arm, a carriage carried follower movable transversely thereof and held in contact with the blade surface being recorded whereby the position of the follower at any radius is a function of the radial position of the arm, a cylinder carried by the carriage and having thereon a paper wrapping, a follower actuated recording marker movable with the carriage and bearing on the paper wrapping, and means to turn the cylinder on its axis in response to movement of the carriage along the radial arm so as to move the pa per wrappings under the marker, said last mentioned means including a cord anchored adjacent the propeller axis and wound about a cylinder actuating drum of tapering diameter to compensate for the thickness of the wrapping on the cylinder.

4. A pitchometer for preparing a chart to show the departures of the'surface of a screw propeller blade or the like froman ideal blade surface whereby the pitch of the propeller may be recorded, comprising a'radially extending swing able arm, means for rotatably supporting the-arm co-axially of the propeller whereby the arm is 4 adapted to be placed in various radial positions opposite the sloping surface of the propeller blade, a radiallymovable carriage on the'arm; a horizontal cylinder carried by the carriage, a selfwinding paper storage cylinder, a paper wrapping extended from the storage cylinder and secured to the first cylinder, means to turn the first cylinder on its axis in response to movement of the carriage along the radial arm so asto wind and unwind the paper wrapping, a horizontally movable marker supported by the carriage, a vertically movable follower supported by the carriage and bearing on the blade surface, and a marker operating cord connected with the follower. i

5. A pitchometer such as claimed in claim 4, having duplicate mounting means for the follower at different points lengthwise of the carriage and cord guides for the marker at corresponding points.

6. A pitchometer for preparing a chart toshow the departures of thesurface of a screw propeller blade from an ideal blade surface whereby the pitch of the propeller may be recorded, comprising a radially extending swingable arm having guides projecting radially of the arm, means for rotatably supporting the arm co-axially of the propeller whereby the arm is adapted to be placed in various radial positions opposite the sloping surfaceof the propeller blade, a carriage, means for mounting the carriage on the arm comprising rollers "bearing against the guides, a carriage carried follower movable transversely thereof and held in contact with the blade surface being recorded whereby the position of the follower at any radius is a function of the radial position of the arm, a cylinder carried by the carriage and having thereon a paper wrapping, a follower actuated recording marker movable with the. carriage and bearing on the paper wrapping, and means to turn the cylinder on its axis in response to movement of the carriage along the radial arm so as to move the paper Wrappings under the-marker.

7. A'recording pitchometer having a horizontal arm swingable. about the axis of a propeller or the like, a carriage movable along the arm, a follower slidably carried by the carriagefor vertical movement, a carriage supported frame, a frame carried horizontally disposed cylinder about which paper is wrapped to provide a recording surface, a frame carried self-winding storage cylinder parallel with the first cylinder, a cord'receiving drum drivingly connected with the wrapping receiving drum, a cord wrapped about the drum and adapted to actuate the drum to draw paper onto the cylinder, a horizontally movable marker carried by the frame and bearing on the wrapping on the first cylinder, and a marker operating cord connected to the follower whereby the position of the marker transversely of the wrapping varies according to the elevation of the propeller blade surface with which the follower is in contact.

8. -A recording pitchometer such as claimed in claim 7, wherein the follower is securedto vertically adjustable guides whereby its position relative to the arm may be varied, and wherein the cord co'nnection'to the marker can'be altered.

9. A recording pitchometer such asclaimed in claim 7 having an anchorage adjacent the propeller axis for the cylinder operating cord so that the paper wrapping is wound onto and off from the receiving cylinder as the carriage is moved back and forth along the arm.

10. A recording pitchometer such as claimed in claim 7, wherein the drum is of varying diameter to compensate for the thickness of the paper wound on the cylinder.

11. A recording pitchometer such as claimed in claim 7, having means to lock the carriage against movement along the arm, a second drum to which the cylinder operating cord is connected and means for operating the second drum in response to swinging of the arm at a speed equal tothe linear speed of the follower about the propeller axis.

12. A recording pitchometer such as claimed in claim 7, having means to lockthe carriage against movement along the'arm, a second drum to which the cylinder operating cord is connected and rack and pinion means for. operating the second druni'in response to swinging of the arm atja speed equal to the linear speed of the follower about the propeller axis.

13. A pitchometer for preparing charts showingrthe profilesof the surface of a propeller blade or the like in either a plurality of radial planes or at a plurality of radii, comprising a radially extending arm adapted to be swung about the propeller'axis or to be locked in selected radial positions, acarriage movable along the arm and lockable in selected'positions, a carriage support ed follower movable parallel with the propeller axis and bearing on the propeller blade surface, a

marker operable by the follower, two carriage supported cylinders, one being a self-winding paper storage cylinder, the other being a receiving cylinder onto which paper may be wrapped to provide a recording surface cooperative with the marker, cord operated means to rotate the paper receiving cylinder to draw paper onto the same, and two alternatively usable cords actuating means, one acting in response to movement of the carriage along the arm when the arm is it locked against swinging movement tomove the paper at a linear speed equal to the linear speed of the carriage along the arm, the other acting in response to swinging movement of the arm when the carriage is locked at the selected radius to move the paper at a linear speed equal to the linear speed of the follower.

14. A pitchometer for preparing a chart to show the profiles of a propeller blade surface at selected radii comprising a radially extending swingable arm, means for rotatably supporting the arm co-axially of the propeller whereby the arm is adapted to be swung opposite the sloping surface of the propeller blade, a carriage, means to lock the carriage on the arm, a carriage carried follower movable transversely thereof and held in contact with the blade surface being recorded whereby the position of the follower at any radius is a function of the radial position of the arm, a cylinder carried by the carriage and having thereon a paper wrapping, a cord receiving drum for actuating the cylinder, a cord, a follower actuated recording marker movable with the carriage and bearing on the paper Wrapping, and means to turn .the cylinder on its axis in response to the swinging of the arm so as to move the paper wrappings under the marker, said means including a lockable sector, a pinion swingable by the arm and in mesh with the sector, a drum operated by the pinion at a surface speed equal to the speed of the follower in the are through which it moves, and about which the cord is wrapped.

15. A pitchometer such as claimed in claim 14, wherein the sector is carried on a plate swingable about the propeller axis and lockable in position.

IVAN D. EBY. 

